Installation Guide and Reference

Create a System Backup to Tape

Using this scenario, you can create and verify a bootable system backup, also known as a root volume group backup or mksysb image.

Step 1. Prepare for System Backup Creation

Before creating system backups, complete the following prerequisites:

• Be sure you are logged in as root user.
• If you plan to use a backup image for installing other differently configured target systems, you must create the image before configuring the source system, or set the RECOVER_DEVICES variable to no in the bosinst.data file. For more information about the bosinst.data file, refer to The bosinst.data File in the AIX 5L Version 5.2 Installation Guide and Reference.
• Consider altering passwords and network addresses if you use a backup to make master copies of a source system. Copying passwords from the source to a target system can create security problems. Also, if network addresses are copied to a target system, duplicate addresses can disrupt network communications.
• Mount all file systems you want to back up. The mksysb command backs up only mounted JFS (journaled file systems) in the rootvg. To back up file systems, use the mount command.
  Note
  The mksysb command does not back up file systems mounted across an NFS network.
• Unmount any local directories that are mounted over another local directory.
  Note
  This backup procedure backs up files twice if a local directory is mounted over another local directory in the same file system. For example, if you mount /tmp over /usr/tmp, the files in the /tmp directory are then backed up twice. This duplication might exceed the number of files that a file system can hold, which can cause a future installation of the backup image to fail.
• Use the /etc/exclude.rootvg file to list files you do not want backed up.
• Make at least 8.8 MB of free disk space available in the /tmp directory. The mksysb command requires this working space for the duration of the backup.

  Use the df command, which reports in units of 512-byte blocks, to determine the free space in the /tmp directory. Use the chfs command to change the size of the file system, if necessary.

  For example, the following command adds 12 MB of disk space to the /tmp directory of a system with 4 MB partitions:

  # chfs -a size=+24000 /tmp

• All hardware must already be installed, including external devices, such as tape and CD-ROM drives.
• The bos.sysmgt.sysbr fileset must be installed. The bos.sysmgt.sysbr fileset is automatically installed in AIX 5.2. To determine if the bos.sysmgt.sysbr fileset is installed on your system, type:

  # lslpp -l bos.sysmgt.sysbr

  If the lslpp command does not list the bos.sysmgt.sysbr fileset, install it before continuing with the backup procedure. Type the following:

  # installp -agqXd /dev/cd0 bos.sysmgt.sysbr

Step 2. Create a System Backup to Tape

1. Enter the smit mksysb fast path.
2. Select the tape device in the Backup DEVICE or File field.
3. If you want to create map files, select yes in the Create Map Files? field.

   For more information, see Using Map Files for Precise Allocation in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices.

   Note
   If you plan to reinstall the backup to target systems other than the source system, or if the disk configuration of the source system might change before reinstalling the backup, do not create map files.
4. To exclude certain files from the backup, select yes in the Exclude Files field.

   For more information, see Excluding Files in System Backups in AIX 5L Version 5.2 Installation Guide and Reference.

5. Select yes in the List files as they are backed up field.
6. Use the default values for the rest of the menu options.
7. Press Enter to confirm and begin the system backup process.
8. The COMMAND STATUS screen displays, showing status messages while the system makes the backup image. When the backup process finishes, the COMMAND: field changes to OK.
9. To exit SMIT when the backup completes, press F10 (or Esc+0).
10. Remove the tape and label it. Write-protect the backup tape.
11. Record any backed-up root and user passwords. Remember that these passwords become active if you use the backup to either restore this system or install another system.

You have successfully created the backup of your rootvg. Because the system backup contains a boot image, you can use this tape to start your system if for some reason you cannot boot from hard disks.